[F4C]

Perhaps once you move beyond the middle of November, any rebrand/refresh won't have chance to land with viewers before the launch of your Christmas idents.  It will simply be lost to most until January.

It's probably best now just to wait until January and do it with some fanfare.

Or… the Christmas idents could be a taster of the new look. Or a transitional package, like what S4C did in 2007.